'Artificial leaf' makes hydrogen from solar cell

[floatingdog]

By Richard Adhikari
TechNewsWorld
03/28/11 12:20 PM PT

Scientists at MIT have created what may be the first practical artificial leaf -- a device about the size of a playing card capable of splitting water into hydrogen and oxygen and storing the energy in a fuel cell. Placing the leaf it in a single gallon of water in sunlight could produce enough electricity to supply a house in developing countries with its daily electricity requirement, according to researchers.

http://www.wired.com/wiredscience/2011/03/artificial-leaf/

http://www.technewsworld.com/story/...rify-an-Entire-Home-72156.html?wlc=1301377932

http://news.google.com/news/more?pz=1&cf=all&cf=all&ncl=dgYnqO4yYiP1vVMbEfnrw0ddEvyPM

 

[hydro-one]

YYYYYYYYYYYEEEEEEEEEEEEEEEEEHHHHHHHHHHHAAAAAAAAAAAA

Ive been waiting for this . the holy grail of chemistry IMO. If it works. were all gonna be ripping electric soon, carbon free

 

[x88x]

Intruiging, but color me skeptical.

336TWh (14TW * 24h) from one gallon of water? Yeah, I'll believe it when I see it.

...also, who the heck has a "14-terrawatt need"? (quote from Wired article).

There's also some inconsistencies in the articles..the technewsworld article at one point mentions 100mA/cm^2, then a couple paragraphs later mentions 1,000ma/cm^2.

Also, if they're only worried about getting the tech to developing countries that need cheap, plentiful power, how about we see the formulas/designs/etc open-sourced?

Don't get me wrong, I'll be the first to applaud it if it really works (or they post some consistent numbers), but there's too many unknowns flying around...right now it reeks of a free-energy scheme, even if the source does lend a bit of credence. If this does actually work like they say, though, having a way to fill a fuel cell on the fly (or at least not having to store nearly as much) instead of storing lots of volatile hydrogen would be a great boon to fuel-cell tech.

BTW, here's another article the source article for at least some of the blogs in the google news link:
http://portal.acs.org/portal/acs/corg/content?_nfpb=true&_pageLabel=PP_ARTICLEMAIN&node_id=222&content_id=CNBP_026944&use_sec=true&sec_url_var=region1&__uuid=5fc55389-fc76-4808-9914-9b8fd94d13d2

 

[Joe Perez]

Intruiging, but color me skeptical.

336TWh (14TW * 24h) from one gallon of water? Yeah, I'll believe it when I see it.

...also, who the heck has a "14-terrawatt need"? (quote from Wired article).

I don't normally dabble in tinfoil-hat threads, but I think you may have misinterpreted this a bit.

Quoting the Wired article: "Provide every house on the planet with an artificial leaf and we could satisfy our 14-terrawatt need with just one gallon of water a day."

Translation: "If we provide one artifical leaf to every house in the world, then by using one gallon of water per house per day, the entire world's combined energy requirement of 14Tw (continuous) could be satisfied."

It's actually not nearly as spectacular of a claim as it sounds when you put it that way. Still pretty optimistic, but not "Keanu Reeves invents bubble fusion" optimistic.

There are 6.9 billion people in the world. Granted, not all of them live in houses, but we'll handwave over that for the moment and just assume that, each house contains five people. That's about 1.4 billion houses.

We'll assume that the 14 Tw figure is accurate. Actually, an uncited note at the Wikipedia Entry on Orders of magnitude (power) lists total global power use at 15 Tw, so that number may be accurateish.

14 Tw / 1.4 billion houses = 10 Kw per house average. Seems a bit high to me, but of course we failed to account for all of the industrial uses of electricity worldwide. I, for one, probably consume more electrical power at my place of business than I do at home.

So, do you think that there's enough hydrogen in one bucket of water to produce 10 kilowatts continuously for one day (240 Kw/h)? It's probably not all that far-fetched of an idea. We just have to assume that the Magic Leaf actually does what they say.

 

[Arlo1]

Have to follow this there has been a few people working on this!

 

[neptronix]

could produce enough electricity to supply a house in developing countries with its daily electricity requirement, according to researchers.

So in other words, no dishwasher, no AC, no playstation 3, no tv, no heat, only 1-2 lights during the night, and maybe a cell phone power charger or a power tool here & there.

He has shown that a prototype of his leaf in the laboratory operated continuously for at least 45 hours without a drop in activity.

I'll be excited when it runs for more than 2 days

 

[REdiculous]

So, do you think that there's enough hydrogen in one bucket of water to produce 10 kilowatts continuously for one day (240 Kw/h)? It's probably not all that far-fetched of an idea. We just have to assume that the Magic Leaf actually does what they say.

Maybe there's 10kw worth of hydrogen in a bucket of water but the leaf would have to absorb over 10kw worth of sunlight in order to make the hydrogen and there would be losses from converting the hydrogen to electricity. Why not skip the hydrogen step(s) and just use solar panels in the first place?

 

[Joe Perez]

Why not skip the hydrogen step(s) and just use solar panels in the first place?

Assuming that the mechanism of action is conventional hydrolysis, you're quite right.

So far as I can tell, however, this invention relies upon "magic", so it's entirely possible for the net energy output to exceed the gross energy input by several order of magnitude.

(takes off Devil's Advocate hat)

 

[Arlo1]

Why not skip the hydrogen step(s) and just use solar panels in the first place?

Assuming that the mechanism of action is conventional hydrolysis, you're quite right.

So far as I can tell, however, this invention relies upon "magic", so it's entirely possible for the net energy output to exceed the gross energy input by several order of magnitude.

(takes off Devil's Advocate hat)

Magic hu? So you are telling me that spliting H20 Is magic? Or just using the sun to do it???? If someone can use the sun to do it than it has potential to make Hydrogen fuel cells and many more things a lot more feasible!

 

[REdiculous]

So far as I can tell, however, this invention relies upon "magic", so it's entirely possible for the net energy output to exceed the gross energy input by several order of magnitude.

The output has to be less than the input or they could simply shine a light on the "leaf" to create the hydrogen to drive a fuel cell to power the light...perpetual motion? :|

 

[Joe Perez]

Magic hu? So you are telling me that spliting H20 Is magic? Or just using the sun to do it????

It's a matter of scale.

Using a device such as the one described above to extract more useful energy from a bucket of water (in the form of electrolytic separation of hydrogen) than the total amount of energy input into the process by nearly 4 orders of magnitude* (in the form of solar radiation striking the "leaf"), is by any reasonable definition of the word, magic.


It's one thing to harness the "free" energy raining down from above. It's quite another to multiply that energy in the manner of Christ dividing fishes and bread.


* = The following assumptions are made:
1: A standard playing card measures 2.5" x 3.5", for a total area of 8.75 in^2, or 0.06 ft^2.
2: The amount of total solar energy striking a 1 ft^2 area in full sunlight is appx. 100 watts. (Note that this is total energy, not merely energy recoverable by present-day photovoltaic means.)
3: Thus, assuming 12 hours of full sunlight per day, a playing card will be struck by a total of 72 watt-hours of energy per day.
4: The claimed invention, by earlier estimates, should produce appx 240 Kw/h per day in order to meet the stated goals.

 

[Kingfish]

The story was reposted today on MSNBC: 'Artificial leaf' makes real fuel

Reading the thread: I think the idea here is that you have a device that can directly use solar to convert water into molecular Oxygen and Hydrogen without other intermediate processes. In other words, Create electricity (however achieved), then Electrolysis, verses this new One-Step solid-state device through catalytic reaction. I wouldn’t read anymore into it than that.

The design of the device is fitting for applications where power to drive electrolysis may not be available, although plentiful in solar and water; remote locales, military activity, and space exploration. Perhaps the device could be applied to industrial applications such as rocket fuel for Cape Canaveral, or manufacture of a myriad of other products benefiting from the utility at a macro level.

Augmenting Mr. Fusion-type fuel cell systems for homes though seems quite a bit farther down the road; the cost to create power needs to come down to make it viable for the home. Maybe these folks doing the research could apply their talents into that realm to craft an efficient converter that likewise does not depend upon rare or costly components; an apple and carrot at each end would be ideal! 8)

Energized, KF

 

[scotticeberg]

If we build enough solar panels, wind turbines, and solar thermal installations we will have a surplus of electricity to split water into hydrogen and oxygen. Hydrogen is the ultimate storage medium. It takes a lot of energy to split water into oxygen and hydrogen, but its worth it. We could kiss most pollution good bye, but we would rather slowly die.

There is ass loads of wind and sun out there for us to harness. However, I guess free, clean, abundant energy is just too "expensive".

 

[Jay64]

If we have a surplus of energy, why would we need to make hydrogen? There are a lot of developing countries that are at a loss for water in a lot of places. Hell, even in the US a lot of places are very scarce on water. Why would they want to take their precious resource and use it to make less energy than they had to start with? I grew up in an area that didn't have govt. supplied water. We had to catch rain water, and during droughts we had to haul water in. When you live in those conditions you don't want to waste your water on anything besides the essentials. I like technology, but I am always kind of a little taken back when people talk about breaking apart water for energy.

 

[oldpiper]

If we have a surplus of energy, why would we need to make hydrogen? There are a lot of developing countries that are at a loss for water in a lot of places. Hell, even in the US a lot of places are very scarce on water. Why would they want to take their precious resource and use it to make less energy than they had to start with? I grew up in an area that didn't have govt. supplied water. We had to catch rain water, and during droughts we had to haul water in. When you live in those conditions you don't want to waste your water on anything besides the essentials. I like technology, but I am always kind of a little taken back when people talk about breaking apart water for energy.

If we were to have a surplus of energy (not just enough to fulfill our needs), then conversion to H2 could be a way of storing it for high-demand/low production periods (like rainy days with a solar system). An H2 pipeline might also be a reasonable way to get water to a drought-stricken area, at least sufficient for drinking/cooking/animal needs/etc. The heat from the combustion at the end of the pipeline could then be used to provide heat during the night, since radiative cooling is highest without cloud cover.

If we can find a way to give the world a surplus of usable energy without messing things up through pollution or adverse climate change (even with solar energy, that energy from sunlight that is captured isn't being put to use by Nature to keep local conditions stable, whatever they are), then a whole raft of problems go away. Then, maybe even the Republicans will start believing in Science. :lol:

Cameron